Some would argue that the flip out screen is not a gimmick and is actually practical in some applications.
As someone who does video, I'd agree with you. I don't need it, as I could get every shot I now get with my 60D on my 50D, but it makes some things more convenient.
But, I say it as a bad thing on the T3i because they put it on a T2i and changed nothing else for 95% of end users (the other 5% being those that use slave flash on a T3i, and that is probably an overestimation). If it was such a necessary item, why wasn't it on the camera's earlier; they've had the tech for long time. They just suddenly needed something to differentiate it and charge a premium...
The touch-screen might actually be useful since the button arrangement has always been awful on the Ti cameras, they're desire to include very few buttons might work. We'll see.
I'm interested if this has anything to do with mirror-less.
The general consensus is that any Canon mirror-less won't be EF mount...since the point of mirror-less is to be smaller, and the EF mount makes the camera about twice as large as it'd need to be. More likely its just another light, portable lens like the 50mm f/1.8.